Hot electron transport in two dimensional electron gas

We demonstrate ballistic transport of hot electrons in a high mobility two dimensional electron gas (2DEG) over distances as large as two micrometers and tunneling through a barrier induced in the 2DEG. Various inelastic scattering mechanisms are studied experimentally. For electrons with excess energy larger than the longitudinal optical (LO) phonon energy quanta we show sequential emission of up to three phonons. Below that energy we find a surprisingly long mean free path, approximately an order of magnitude longer than expected theoretically for electron-electron scattering. The combination of a very short mean free path for LO phonon emission and the long mean free path below the phonon energy leads to a new type of periodic oscillations in the maximal energy of the collected electrons. Finally we report on a study of the angular distribution of hot electrons injected from a point contact and demonstrate electrostatic steering of the electronic beam.